The book by the venerable French historian Roland Mounier is dedicated to a significant date in the history of France - the day when the French king Henry IV was killed. Through the prism of murder, Mounier examines the mentality of French society at the beginning of the 17th century, which was experiencing the consequences of the tragic Wars of Religion. The book presents a whole range of subjects: the foreign policy of France during the reign of the first king from the Bourbon dynasty, the relationship between the sovereign and the people, the ideal image of the king in the eyes of his subjects, the maneuvering of the French government between Protestants and Catholics. Answering the question of who killed Henry IV, Roland Mounier simultaneously makes his diagnosis of French society at the beginning of the 17th century.